Control system



4 SHEETS-SHEET 1.

INVENTOR Hen/jy@ Jn/@.5

BY v

ATTRNEY H. D. JAMES.

CONTROL SYSTEM.

APPLICATION FILED AUG.I0, 1918.

Patented Sept. 27

-WITNESSES t @uw w JM H. D. JAMES.

CONTROL SYSTEM.

APPucATloN FILED Aue.1o,|91e.

Pamd sept. 27,1921.

4 SHEETS-SHEET 2.

WITNESSES:

, I v INVENTOR Henry D. James ATTORNEY H. D. JAMES.

CONTROL SYSTEM.

APPLICATION mio Ammo, |918.

1,392,057, Patented Sept. 27, 1921.

4 SHEETS-SHEET 3.

F/y. 8 i Z W|TNESSES INVENTOR Hen/y D. James ATTORNEY H. D. JAMES.

CONTROL SYSTEM.

APPLICATION man Ammo, 191s.

1,392,057, PatentedSept. 27, 1921.

4 SHEETS-SHEET 4.

WITNESSES:

- INVENTOR /wwf Hen/ g D, Jam

. v BY ATTORNEY UNITED STATES PATEN'I" OFFICE..

HENRY D. JAMES, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF IEE1\T1\`|'SYIVANIA.

CONTROL SYSTEM.

Application led August 10, 1918. Serial No. 249,344.

T 0y all whom t may concern Be it known that I, HENRY D. JAMES, acitizen of the United States, and a resident of Edgewood Park, in thecounty of Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in Control Systems, of which the following is aspecification. Y

My invention relates to reversing systems for electric circuits,especially electric motors, and is particularly adapted for use invconnection with motor-control systems of the character set forth in mycopending application, Serial No. 236,937, filed May 27, 1918, controlsystems.

The dominant feature of the systems of my said application is that acoil designed to actuate the relays for controlling the contactors whichshort-circuit the accelerating resistor is shunt-connected across theterminals thereof. The relays may be of the type illustrated in acopending application by De Camp, Serial No. 241,259, filed June 21,1918, and assigned to the Westinghouse Electric & Manufacturin Co., orthey may be of any ordinary type. n the latter event, a separateactuating coil may be employed for each relay, all the coils beingconnected in multiple with the resistor.

As explained in my above-mentioned application, means must be provided,owing to n object of my invention is to provide a.

safe starting system for a motor so controlled.

Another object of my invention is to provide a reversing system for amotor governed by such a controlling system.

Other objects yof my invention will be made clear hereinafter.

If relays be employed of the type described 'in the aforementionedapplication by De Camp, in which a main armature controls the closing ofthe relays, I may so arrange the control circuits that it will beimpossiblethe motor is started. I may effect this object.

electrically or mechanically.

If the mechanical method be employed, the main armature may be sodesigned as to be actuated to its normal position, upon the reversal ofthe motor, by a projectlon carried by a bar connecting the reversingcontactors. If the electrical method be adopted, the main armature may,itself, be a contactbearing member, the contact members of which mayinitially close the motor circuit when the armature member occupies itsnormal, inoperative position, after which the Contact members may beshort-circuited so as not to break the starting circuit upon theactuation of this armature member to its operative osition.

I have e-rein illustrated several systems embodying this principle. Thecircuits may be so arranged as to prevent the reversal of the' motoruntil after a time interval has elapsed, caused by the Areversal of themagnetism of the coil for controlling the relays. I have alsoillustrated one lmethod of revensing a motor the acceleration of whichis effected by the use of ordinary relays having individual actuatingcoils. y

My invention will vbe understood by reference to the accompanyingdrawings, in

which Figures 1, 2 Yand 3 are,y respectively, a

side and an end elevation and a plan view of a relay of the typeillustrated in the aforementioned application by De Camp.v

Fig. 4 is a detail kof a modification of this v relay. Fig. 5 is adiagrammatic view of clrcuits and apparatus illustrating one form of myinvention as applied an accelerat-f ing` system employing a relay of thetype shown in Figs. 1 to 3. Figs. 6 and 7 are similar views ofmodifications. F ig. 8 is a modified system employing a relay, a detailof which is illustrated in Fig.. 4. Fig. 9 is a reversing system,arranged according to my invention, employing ordinary relays.

As' my invention is of particular value in connection with a systememploying the De Camp relay above referred to, and illustrated in Figs.1 to 4 it Will conduce to clear-,.

ness to describe this relay first.

An insulating panel 29 carries two brackets 30 and 31 supporting thecoils 22 and 23 which, when energized by currentl flowing through them,create magnetic fields for attracting an armature 32 and armatures .33,34 and 35. A compression spring 36 is adjustably mounted upon anon-magnetizablel rod 37 that is slidably mounted in projections 38 and39 which are integral with a member 31. The projection 38 'serves alsoas a pole piece for the armature 32 and the projection 39 as a polepiece for the armatures 33, 34 and 35. A bar 40 is rigidly -connected tothe rod 37 and normally enby a relatively weak spring 43. The bracket 30supports a non-magnetizable U-shaped member 44 between the arms of whichare pivotally mounted the armatures 33, 34 and 35, which carry,respectively, the movable Contact members 45, 46 and 47 of the relays25, 26 and 27. The corresponding stationary ,contact members 48, 49 and50 are mounted upon the insulating panel 29.

Springs 51 are attachedto longitudinally adjustable members 52 and tothe other ends of the members 41. The pole piece 39 is f, ber 56 may bereplaced by a switch vmemberv provided with longitudinally adjustablemembers 53 to regulate air gaps 70 between these members and thecorresponding armatures. By means of this adjustment, or by means of the-members 52, which control the `tension of the springs 51, the action ofthc magnetic fluxproduced by the coils 22 andl 23 may be so regulatedthat the armatures 33, 34 and 35 will be operated in proper sequence.

v The armature 32 is provided with an extension 54 of insulatingmaterial which carries a switch member 55 for coperating with stationaryswitch members 5,6 mounted upon the insulating panel 29. As shown inFig. 1, the switch members 55 and 56 .are closed when.- the armature 32occupies itsl open position. If desired, ythe switchmem- 57 Fig. 4, sothat contact between the switch members 57 and 55 Vwill be madeywhen thearmature 32 occupies its closed position.

The operation may be briefly described as follows: Upon current flowingthrough the coil 22, a magnetic field is created which [causes .thearmature. 32 to be attracted to- 'ward the'pole piece 38. The for'ce'ofthe spring 36 is thereupon overcome, and the `trated in Fig. 5.

Amembers 55 and 56.

lof successive portions 13, 14 and 15 of the bar 40 is moved out ofengagement with the armatures 33, 34 and 35, the stop members 41 ofwhich are, nevertheless, maintained in engagement with the pole piece 39until the flux of the magnetic field becomes successively suflicientlylow to permit the springs 51 to successively actuate the movable contactmembers 45, 46 and 47, thereby to close v the relays 25, 26 and 27.v Inthe event that the magnetic field 'becomes too weak to hold 75 thearmature 32 in its elevated position, the spring 36, becoming released,will separate the movable from the stationary contact members. Actuationof the armature 32, of

course, effects corresponding actuation of the switch member 55.

I shall now describe the invention illus- A motor, the armature of whichis shown at 1 and the shunt fieldmagnet winding at 2, is connectedbetween line conductors 3 and 4, with a regulating resistor 6 normallyin series with the armature 1. A plurality of reversing contactors 58,59, 60 and 61 control the direction of rotation of the motor. A mastercontroller or switch 7 controls the actuation of the reversingcontactors through the medium oi energizing coils 62, 63, 64 and 65,which are connected in lcircuits including the contact members 55 and56.

The movable contact members of' contactors 66 and 67 are, respectively,mechanically interloc'ked with the movable contact members of thereversing contactors 58 and 59 to provide shunt circuits for the contactrlhe master controller` 7 is designed to close contact members 9 and 18.One or more contactors 10, 11 `and 12 (three are illustrated) controlthe shunting y,

regulating resistor 6 through the medium of energizing coils 19, 20and21. The coil 22 is connected across the terminals of the resistor 6. at79 and 80. The energizing of the coil 22 causes the successive closingof the 110 relays 25, 26 and 27, as above described, in accordance withthe strength of the current passing through the coil 22.

The coil 19 is connected in a circuit lead- .ing from the line conductor3, bythe conductor 28, through thev reversing contactor 59, (assumingthis contactor and the contactor 60 to be closed) the armature 33 andthe relay 25 to` the point 79 and from that point, through the reversingcontactor 60 120 to the line conductor 4. If the reversing contactors 58and 61 are closed instead, the current thrOugh the coil 19 is in thereverse direction. The coils 20 and 21 are similarly connected to therelays 26 and 27., The coil 125 23 is connected, vby conductor 28,l inparallel with thecoil 21 and in series with a high resistance 24, sothat the current in the coil 23, likel that in the coils 19, 2O and 21,

is reversed when the motor is reversed.

Upon moving the controller 7l to the left, a'circuit is established fromthe line conductor 3 through the controller arm 7, which is electricallyconnected thereto, the con- 5 tact member 9, the coils 63 and 64 inparallel, one'of the contact members 56, the contact member 55 and theother contact member 56 to the line conductor 4, The coils 63 and-64are. thereupon energized -to 1o cause the closing of the reversingcontactors `59 and 60. A circuit -is now established extending from theline conductor 3, by the conductor 28a, through the reversing contactor59, the motor armature 1, the resistor 6, the point 79 and the reversingcontactor 60,v to the line conductor 4. A. shunt circuit is` establishedthrough the field-magnet winding 2 when the main-line switch (not shown)is closed. A circuit is also established through the coil 22 in parallelrelation to the resistor 6, the coil 22 and the resistor 6being-connected at -points 80 and 79.

The energizing ofthe coil -22 creates a 25 magnetic lfield whichattracts the armature 32y to the pole piece 38 andwinstantly separatesthe contact members 55 and 56. This separation breaks the circuit, abovedescribed, of the coils 63 and 64." Holding circuits for these coilshave previously been established, however, b the contactor 67,mechanically interlocke with the reversing contactor 59. The rod 37 isactuated by the armature 32, in opposition to the Jforce of the spring36, to force the bar 40 away from the armatures 33, 34 and 35.

If the current is above a previously-selected safe value, the flux ofthe magnetic vfield created by the coil 22 will overcome 40 'the forcesof thesprings 51, and the armatures 33, 34- and 35 will remain with thestops 41 in engagement with the pole piece 39 (Fig. 1). As the motoraccelerates and the current decreases in value the magnetic 45 flux setup by the -coil 22 diminishes..

When the i'luX has decreased to a predetermined yvalue, the spring '51attached to the armature 33 will overcome the force VeX- erted bytheflux of this field so that the relay 25, controlled by the armatureV 33,will be closed. The time when this operationwill occur will depend uponthe width of the air gap 70 and the tension v.of the spring 51. Thearmatures 34and 35, however, will remain open; The closing of the relay25 4establishes a circuit which extends from the.

line conductor 3, by the conductor 28a, through the reversing contactor59, the armature 33, the contact members 45 and 48 0 of the relay '25,and the actuating coil 19 to the point 79 and fromthere, through thereversing contacter 60, to the llne conductor 4. 'The coil .19 becomingenergized.the contactor 10 becomes closed to short-circuit, the

portion 13 of the resistor 6. The motor then further accelerates, and,by'decreasing the voltage across the terminals of the coil 22, themagnetic field in the neighborhood of this coil is further weakenedwhich permits the closing of the second relay 26 con-- trolled by thearmature 34. ,A circuit is then made from the line conductor 3, by the)conductor 28a, through the reversing contactor 59, the armature 34, thecontact members 46 and 49, the coil 20 and the reversing'contactor 60 tothe line conductor 4. The coil 20, thus becoming energized, causes theclosing of the contactor 11 and the consequent shunting of a secondportion 14 of the resistor 6.

After the motor has accelerated further, the magnetic field surroundingthe coil 22 is again weakened and the relay 27 is closed, creating acircuit extending from the line conductor 3, by the conductor 28a,through the reversing contacter 59, the armature 35, the contact members47 and 50, 'the coil 21 and the reversing contactor 60'to the lineconductor 4, thereby causing the closing of the contactor 12 and theshunting of the third portion 15 of the resistor 6.` The whole resistor6 is then entirely shunted from the armature circuit and the armature 1is oon-- nected directly across the line.

The shunting of the resistor 6 denergizes the coil 22 which wouldrelease the armature 32 and cause the relays 425, 26 and 27 to bere-opened, thus resulting in de'nergization of the coils 19, 20, and 21and the consequent re-insertion of the resistor 6 into the armaturecircuit, except for the coil 23, which becomes energized at the sametime with the coil 21 upon the Iclosing of the armature 35 of the relay27. The coil 23 is connected in a circuit extending from the lineconductor 3, by the conductor 28a, through the reversing contacter 59,the darmature 35, the contact members 47 and 50, the 'conductor 28, thecoil 23, the -resistor 24, the point 79 and the reversing contactor 60to the line conductor 4.

The motor may be stopped by moving the controller army 7 to the ofposition illustrated, thereby denergizi-ng the actuating coils' of thereversing contactors and the consequent opening of the reversing.contactors. The coil 23 is, thereupon, denergized (which lthereuponpermits the opening of the relays 25,26 and 27 as are also the actuatingcoils v19, 20 and 21 of the contacf tors 10, l1 and 12. The motor maythenA be restarted, eitherin the same or -in the tactors will l'yv open.Upon reclosing the controller arm 7, within a limited time thereafter,while the armature 1 is still rotating, the coil 22 is again energized,above the predetermined degree at which the relays 25, 26 and 27 arepermitted to close and cause the reclosing of the contactors 10, 11 and12 to short-circuit prematurely the entire resistor 6. This tends tohave the effect of suddenly throwing the armature 1 into the linecircuit without any resistance in series with it. In my copendingapplication above mentioned, as also in Figs. 6 and 7 of the presentapplication, are illustrated several 4methods for preventing thishappening. The present application is more concerned with the preventingof similar occurrences upon the'reversal of the motor from Jfull speedin one direction to full speed inthe opposite direction. 2 i

.Assuming that the motor -is operating at full speed and that it isdesired to reverse it, the controller arm 7 is moved from, let us say,the extreme left-hand position to the extreme right-hand position ofFig. 5. The circuits of the motor are thereupon opened, as explainedabove, and a new circuit is established from the uline conductor 3through the controller arm 7, the contact member 18, the actuating coil62 of the reversing contactor 58 and the actuating coil of the reversingcontactor 61 in parallel. and the contact members 55 and 56, if closed,to the line conductor 4. v

The contact members 55 and 56, however, will not be closed until'thecoils 22 and 23 are sutliciently denergized. rllhe residual magnetism ofone or both of these coils may maintain the armature 32 open, and therelays 25, 26 and 27 may, therefore, remain closed 4for a limited periodoftime. Upon the closing of thecontact members 55 and 56 and theestablishment of the above-traced circuit, a circuit is established forthe motor which extends from the line conductor 3, by the conductor 28h,the reversing contactor 61, the resistor 6, the armature 1 and the.reversing contactor 58,v to the line con`- ductor 4, the circuit being,in this case, in a direction reverse to that described above.

.The coil 22 is energized in the same manner as above described, but theconnections of its terminals are reversed, to cause the closing4 of thearmature 32 and the consequent release by the bar 40 of the armatures33, 34 and 35. The motor is now started in the opposite direction, butwith the whole resistor in series with the ar'- mature. The relays willnot close simultaneously, as might happen, in the absence of specialprovision thereagainst, if the motor were restarted in the samedirection by reason, of the reversal of -coil 22.

0 polarity of the The decreasing current in the coil 22 will, as before,cause the closing of the armatures 33, 34 and 35 to cause the closing ofthe contactors 10, 11 and 12 to short circuit the resistor 6.

It will thus be seen that, with the system of Fig. l5, the purpose of myinvention, namely, to prevent a reversal of the motor with the resistorshort-circuited from the armature circuit, is accomplished inseveral'ways. The circuits are so arranged that it is impossible, owingto the contact members 55 and 56, to effect the closing of either pairof the reversing switches untily the energization of the coil 22 hasydecreased to a predetermined degree. Frovision is made, also, forreversing the magnetic fields of the coils 22, 23, 19, 20 and 21 whenthe motor circuit is completed 'for operation in the opposite direction.

Another method of effecting this result is illustrated in Fig.6. Thecoils 19, 20 and 21 are here directly controlled by the controller 7,through contact members 16 and 17, instead .of through the reversingcontactors. The coil 19 is connected in circuit as above described. Thecircuit of the coil 20, however, extends from the line conductor 3through the controller arm 7, the contact member 16 or 17, the armature34 and the relay 26, to the connecting point 68 of the resistors 13 and14. When the resistor 13 is included in the circuit of this coil 20, thevoltage is not sulicient to energize the coil 20, and the contactor 11,therefore, remains open. When the contactor 10 is closed, the

circuit is completed to the line conductor 4 through this contacter, andthe coil 20 becomes suiciently energized to close the contactor 11.Similarly, the coil 2l is connected at 69 in a circuit which includesthe relay 27 and the resistors 13 and 14, except when the contactor 11is closed, thereby delaying the closing of the contactor 12 until `thecontactor 11 is closed.,v r

A line contactor 5 is employed in addition to the reversing contactors58, 59, 60 and 61, the coil 8 of which is in parallel circuit with thecoils 19, 20 and 21. The reversing contactors 61 and 60, like thecontactors 66 and 67, are here shownmechanically interlocked with thereversing contactors 58 and 59, respectively, though separate reversingcontactors may, if desired, be employed, as in Fig.` 5. The coils 22 and23 are here shown as continuous, though this is merely a detail.

The operation is as follows: Upon actuatlng the contro-ller arm 7 to theleft, a circuit is established which extends from the line conductor 3,through the controller arm 7, the actuating coil 63 of the reversingcontactors 59 and 60 and the contact members 55 and 56 to the lineconductor 4. The reversing contactors 59 and 60 are thereupon closed toestablish the motor circuit, which extends from the line conductor 3, bythe conductor 28a, through the reversing contactor 59, the armature 1and the reversing contactor 60 to the point 80 and from there, throu hthe resistor 6 and the line contactor 5 to t e line conductor 4.

The line contactor 5 is closed because of the energizing of the circuitincluding the coil 8 and the contact member 16. As above described, thecoil 22, which is connected in parallel with the resistor 6, will causethe closing of the armature 32 and later, the suc- (Lessive closingof'the armatures 33, 34 and 35. The closing of the armature 32 separatesthe contact members55 and 56, but a holdingA circuit for the coil 63 ispreviously closed at 67. This circuit extends from the line conductor 3,through the controller arm 7, the contact member 9, the coil 63, and thecontactor 67 to the line conductor 4.

Theclosing of the armature-33 establishes a circuit which extends fromthe line conductor 3, through the controller arm 7 the contact member16, the armature 33, the contact members 45 and 48 of the relay 25, thecoil 19, the point 79 and the line contactor 5, to the line conductor 4,whereupon the line contactor 10 closes to short-circuit the portion 13of the resistor. 6. The motor circuit now extends through thereversingcontactors and the armature 1, as above described, through the portions15 and 14 of the resister 6, to the point 68, and from there, throughthe contactor 10, to the point 79, and

= from there, through the line contactor 5, to

the linev conductor 4.

lUpon the closing oit the armature 34,'due to the decreasing magnetismof the coil\22, a circuit is established which extends from the lineconductor3, through ,the controller arm 7, the contact member 16, thearmature 34, the relay 26 and the coil 20, to the point 68 and fromthere, through the resistor 13 and the contactor 5 to the line conductor4. As stated above, the voltage of this cir# cuit is not sufficient tocause the closing ot the contactor 11. If, however, the contactor 10 isclosed, thenthe above-described circuit continues romthe point 68,through the contactor 10 to the point 79' and through the line contactor5 to the line conductor 4,

whereupon the contactor 11 becomes closed to short-circuit'the resisto-r14.

Similarly, the closing of the relay 27 will cause the energization ofthe coil 21 to cause the closin of the contactor 12, and the consequents ort-circuiting of the resistor 15.

,The armature circuit will then extend from the line conductor 3 by thevline conductor 28a, through the reversing contactor 59, the armature1,..the reversing contactor 60,.the

j contactor 12, the point 79 and the contactr 5, to the line conductor4. l

The closing of the relay 27 establishes not only the circu`t of the coil21 but also that of the coil 23. `his latter circuit extends theresistor 24 and the coil 23, to the point 79, and thence, through theline contactor 5, to the line conductor 4. `Thecoil 23 thus takes up thework of the coil 22 upon the short-circuiting of the lattercoilcoincident with the 'short-circuiting of the resistor 6.

If it is desired to'reverse the motor, the arm 7 is actuated to theright to make contact with the contact members 17 and 18. The circuit ofthe coil 8 is broken at the contact member 16 but is immediatelyrestablished at the contact member 17. The actuating coil 63 becomesdenergized, but the coil 62 becomes energized, due to the closing of acircuit extending from the line conductor 3, through the controller arm7, the contact member 18, the coil 62 and the contact members 55 and 56,if closed, to the line conductor 4. The switch members 55 and 56,however, will remain open until the magnetism of the coil 23 hassu'ficiently diminished to permit the armature 32 to be opened by thespring 36 (Fig. 1). The relays 25, 26 and 27 will also be opened by thisspring. The coil 22 becomes renergized as soon as the motor circuit isclosed. This circuit eX- tends from the line' conductor 3, through theconductors 28a and 28", the reversing contactor 61, ii' closed, thearmature 1, the reversing contactor 58, the resistor 6, and the linecontactor 5,-to the line conductor 4. The connections of the coils 22and 23 are not reversed as in the system of Fig. 5 and there is not,therefore, the protecting feature of time lag by reason of the reversalof the corresponding magneticgfields. rlhe protection of the motor isatorded by the fact that, in the event that the coil 22 is suffif Acie/ntly energized to cause the premature `closing of the armatures 33,34 and35, the

contactors 10, 11 and 12 will not close simultaneously,`even though thecircuits of the coils 19, i20 and 21 be simultaneously closed by theclosing of the relays 25, 26 and 27. The coil 20 cannot becomesu'liciently energized to cause the closing of the contactor 11 untilthe contactor 10 has closed and not until the contactor 11 closes can`the coil 21 cause the closing of the contactor 12.

The sys ems of' Figs. 5 and 6 have the feature in co mon that it'isimpossible to restart or reverse the motor until the armature 32occupies its normal position and this it lock shall be mechanical. Ihave shown in Fig. 7.

The reversing contactors 58' and 59 of this figure are mechanicallyinterlocked in a well known manner by a bar 72, pivoted at 73, and theends of which are pivotally connected to the reversing contactors. Thebar is provided with a central projection 74 adapted to engage aspring-pressed rod 75, slidably mounted in brackets 76 and 77 and theend of which is adapted to engage a projection 78 rigidly secured to thearmature 32. The parts are so arranged that, upon the actuation of thereversing oontactors from one position to another, the projection 74will engage the rod 75 to Jforce it downwardly into contact with theprojection 78 and thereby cause the opening of the armature 32.

This action releases the spring 36, (.Fig. 1) whereupon the bar 40causes the openin of the armatures 33, 34 and 35. rl`he Such a system`coils 19, and 21, are denergized which insures that the whole resistorwill be in circuit with the armature before the motor is reversed. Adrum controller 7 'has been illustrated in this ligure, though thecontroller of Figs. 5 and 6 may be employed and, conversely, thecontroller of this iigure may be employed in the systems of Figs. 5 and6. ln this connection, it may be stated that, if the reversingcontactors of Fig. 5 were mechanically interlocked with the armature 32,it would be possible to do away with the necessity of employing thecontact members and 56 and the interlock contactors 66 and 67.

The operation of this system is as follows:

Upon the actuation ofthe controller to the left to position a, a circuitis established which extends lfrom the line conductor 3, through theactuating coil 63, the contact member 9 and the controller 7 to the lineconductor 4. The coil 63 is accordingly energized to cause the closingoi the reversing contactors 59 and 60. A circuit is then establishedwhich extends from the line con? ductor 3, by the conductor 28a, throughthe reversing contactor 59, the armature 1, the reversing contactor 60,and the resistor 6 to the line` conductor 4. j

The bar 72 is, at the same time, actuated by the coil 63 about its pivot73 to remove the projection 74 from engagement with the rod to free thearmature 32 which will be closed by the coil 22, the terminals of whichare connected across the resistor 6 at the points 79 and 80. llVheii thecontroller is actuated to the position b, a circuit is established whichextends from the line cond-uci tor 3, through the armature 33, thecontact members 45 and 48 of the relay 25, the actuatingcoil 19 and thecontact member 16 to the line conductor 4, assuming, of course,

c that the armature 32 has been actuated to tst.

closed position by the coil 22 and the armature 33 by the spring 51(Fig. 1).

llii similar fashion, the coils 2O and 21 are laterjclosed at the propertime according to the degree of ncrgization of the coil 22,

ductor 3, through the conductor 28 and' the resistor 24, to the point80. l

The coil 23 may be energized by line voltage, as in Figs. 5 and 6, orthe systems of these two gures may be so arranged that the coil 23 ofthese figures will be energized bv the counter-electromotive force ofthe niotor. The armature 32 will thus be maintained in closed positionand the relays 25, 26 and 27 will remain closed to maintain the resistor6 short-circuited. The controller 7, of course, may be actuated'step-by-step or to the'position d in one step.

f To reverse the motor, the controller 7 is moved in the'oppositedirection, either stepby-step or to the position d in one step,

whereupon the coil 62 will be energized to cause the closing of thereversing contactors 58 and 61. IThe coil 63 becoming denergized, thebar 72, actuated by the coil 62, will cause the positive opening of thereversing switch 59 in opposition to the force of the spring-pressed bar75 and it will furthermore actuate this spring-pressed bar to cause theopening ot the armature 32 and, therefore, the o ening of the relays 25,

26 and 27. This action will have the effect oi ree-inserting theresistor 6 into the armature circuit, which now extends from the lineconductor 3, by the conductor 28h. through reversing armature 1, thereversing contactor 58 and the resistor 6 to the line conductor 4.

The motor will now be o erated in the opposite direction. rllhe co1 22,however, will be energized in the same direction and, it the Vreversaltake place within a Sulliciently limited period or time, the coil 22will be suciently energized to cause thepremature closing of the relays25, 26 and 27. This may be prevented, however, by either the electricalinterlocking feature illustrated in Fig., 6, consisting of tapping thecircuits of the coils 20 and 21 at (iS-.and 69 or by a mechanicalinterlocking device diagrammatically illustrated in. Fig. 7 at 81 and82.

The mechanical interlocking device coinprises so arranging the relaysand contactors that, when the contactor 10 is open,

he relay 26 will. be open and., when the'con- 130 contactor ei, the 11ocontactor but not until the contactor 10` is closed can the relay 26close to cause the closing of the contactor 11. Similarly, not

until the contacter l1 has'closed can the relay 27 be closed to causethe closing of the cntactor 12. l

It is essential that, in the systems of Figs. 5 and, the circuits of thereversing contactors be closed in the open position of the armature 32.In Fig. 8, I have illustrated a system in which the reversing contactorsare closed when the armature 32 occupies its closed position. In thesystem of this ligure the relay is employed, a detail of which is shownin Fig. 4, the contact members 55 and 57 being open when the armature 32is open and closed when the armature 32 is closed.

A pair of reversing contactors, of the type illustrated in Figs. 6 and7, are employed. They are shown interlocked by a bar 72, as in Fig. 7,though this bar is not absolutely essential. A similar bar is preferablyemployed also in the systems of the other igures. If desired, such a barmay be employed in connection with the systems of Figs. 5 and 6. Thecontroller 7 is here shown as comprising three contact members,insulated from each other, adapted to cooperate with statioi'iary`contact members on each side thereof for direct and reverse operation,respectively. 'llwo of the contact members are designed to close beforethe third, although the controller may be so op erated as to close allotthe contact members together. The controller is preferably ot the drumtype, as in Fig. 7, but any other type o't controller may be employed ifdesired. rlhe motor shown in this gure is of the series-field type, butit may be of the shunt-field or compound type. The motors of the systemsof the other figures may also be either series or compound.

A line contactor 5 is employed in addition to the reversing contactors,as in Fig. l6, the actuating coil 8 of this contacter being controlledby the contact members 55 and 57. 4 contactor 83 is mechanicallyinterlocked with the contactor 5 for a purpose later described.

, Assuming that the controller 7 has been moved one step to the left, acircuit is com-l pleted which' extends :from the line conductor 3through the contact member 9a, the actuating coil 63 and the seriesfield-magnet winding 84 to the line conductor 4. The reversmg contactors59 and 60 are thereu on closed, whereupon a circuit is establis ed rfrom the line conductor 3, through the reversin contactor 59, thecontact member 9b,

lthe coll 23,' the resistor 24, the contacter 83,

the conductor 85, the conductor 71, the reversing contactor 60 and theseries fieldmagnet winding 84, to the line conductor 4.

The armature 32 is nthereupon closed, ,f

which closes the contact members 55 and 57, whereupon a circuit isyestablished from the line conductor 3, through the reversing contactor59, the contact member 9", the actuating coil 8, the contact members 57and 55, the conductor 71, the reversing contactor 60 and the seriesfield-magnet winding 84, to the line conductor v4. rlhe line contactor 5is thereupon closed to establish the motor circuit :which extends fromthe line conductor 3, through the reversing contacter 59, thearmaturell, the line contactor 5, the resistor 6, the reversingcontactor 60 and the field-magnet winding 84 to the line conductor 4.

The closing of the contactor 5 causes the opening of the contactor 83,which deenergizes the coil,23. circuit is, at the same timeestablishedacross the terminals of the resistor 6 for the coil 22, which eX- tendsfrom the point 8O to the point 79. The armature 32 is thus initiallyclosed independently of the coil 22. 0n the other hand, the coil 23 isenergized but a brief period, so as not to serve to maintain the relays25, 26 and 27 open. The coil 22, however, will cause :themto close inthe manner previously described. l

Upon the closing of the relay'25, assuming that the controller 7 hasbeen actuated to its final position, a circuit is established whichextends from the line conductor 3, through the reversing contactor 59,the contact member 16, the actuating coil 19, the contact members 48 and'45, the armature 33, the conductor 71, the reversing contactor 60 andthe series field-magnet winding 84, to the conductor 4. This causes theclosing of the contacter l0 and the consequent short-circuiting of theresistor 13. Similarly, the closing of the relay 26 causes the closingot the cont-actor 11 to short-circuit the resistor 14, and the closingof the relay 27 causes the closing of the contactor12to short-circuitthe resistor 15. The closing of the relay 27 establishes also thefollowing circuit: from the line conductor 3, through the; reversingcontacter 59, the contact member 9b, they coil 23,xthe resistor 86,therelay 27, the armature 35, the conductor 71, the reversing contactor60 and the field-magnet winding 84, to the conductor 4. The circuit ofthe coil 23 is thus restablished to maintain the relays closed, thoughtheI coil 22. is denergized upon the short-circuiting ofthe resistor 6.The motor is now connected directly acrossV the line conductors- 3` and4.

To reverse the motor, the controller 7 is moved in the oppositedirection. The circuits above described are thereupon broken reversedirection. l

n new circuits are made at the contact meinbers 18, 18b and 17. Acircuit is first established which extends from the line conductor 3,through the contact member 18a, the actuating coil- 62, and the seriesfield-magnet winding 84 to the line conductor 4, whereupon the reversingcontactors 58 and 61 are closed to partly close a circuit extending fromthe line conductor 3 throu h the reversing contactor 61 to the point 9,thence through the resistor 6, the line contactor 5, whichis open, thearmature 1, the reversing contactor 58 and the field-magnet winding 84to the line conductor 4.

A circuit is established from the line conductor 3, through thereversing contactor 61, the conductors 71 and 85, the contactor 83, theresistor 24, the coil 23, the contact mem- 'ber 18", the reversingcontactor 58 andthe field-magnet winding 84, to the line conductor 4.The coil 23 will thereupon be energized by a current in a directionopposedto that flowing when the motor was operating in the otherdirection. Thearmature 32, therefore, will not be actuated until it isirst returned bythe spring 36 1) to its open position, when themagnetism produced by the newly created current in the coil 23overpowers the residual magnetism of the coil 22.

rllhe armature 32 will then be reac'tuated to closed position when thecurrent inthe coil 23 builds up to a larger value. As soon as thearmature 32 has been returned to its normal position, a circuit isestablished eX- tending from the line conductor 3, through the reversingcontactor` 61, the conductor 71, the contact members 55 and 57, theactuating coil 8, the contact member 18h, the reversing contactor 58 andthe held-magnet winding 84 to the line conductor 4, causing the openingof the contactor 83 and the closing of the contactor 5 to establish themotor circuit above described. Current now, traverses the motor circuitin the opposite direction.

The establishing of the motor circuit, of course, causes the reversal ofcurrent in the coil 22, so that any residual magnetism must rst beovercomenbefore the coil 22, which now performs the function of the coil23, the circuit of which was broken at the contactor 8.3, can besuiiiciently energized to actuate the armatures 32, 33, 34 and 35, thus`providing for the lapse of a sufficient time circuits of the actuatingcoils 19, 2O and 21 will also be found to be traversed byl currentflowing in a direction opposed to that flowing when the motor wasoperating inthe The circuit of the actuating coil 19, for

i example, extends from the line conductor 3,

lthrough the reversing contactor 61, the conductor 71the armature 33,the relay 25, the coil 19, the contact member 17 the reversing contactor58 and the field-magnet winding 84, to the line conductor 4. A certaintime interval will elapse beforethe current in this circuit willenergize the coil 19 suiiciently to overcome the residual magnetism ofthis coil, during which interval of time the contactor 110 must be open.It will later close to short-circuit the resistor 13. Similarly, thecontactors 11 and 12 will later be closed to short-circuit the resistors14 and 15.

rlhe closing of the contactor 12 is effected by the'closing of thecircuit extending from the line conductor 3, through the reversingcontactor 61, the conductor 71, the armature 35, the relay 27,theactuating coil 21, the contact member 17, the reversing contactor 58'and the field-magnet winding 84, to the line conductor 4. A branchcircuit is, at the same time, established from the relay 27, through theresistor 86, the coil 23, the contact member 18"-, the reversingcontactor 58 and the field-magnet winding 84, to the line conductor 4 toreestablish thecircuit of the coil 23 upon the short-circuiting of thecoil resistor 6.

.lt will be noted that, in the systems of Figs. 5 and 8, a triple checkagainst starting 22 caused bythe short-circuiting of the the motor inthe reverse direction, with the .pointed out that, though ll preferredto einploy the De Camp relay, the invention is not limited thereto, butmay be adapted to control systeins embodying the use of ordinary relays.lin Fig. 9, l illustrate one method oi reversal for such a controlsystem. rllhe relays 25, 26 and 27 are here of the ordinary type, eachenergized by an individual coil 22, 22b and .220. The relay 25 isprovided with a, switch member 55a mechanically interlocked therewith,this switch member being open hen the relay is closed and closed whentheielay 25 is open.

The reversing contactors, of the interloclred type shown in Figs. 6, 7and 8, are

gri

troller 7 .is of the form illustrated in Fig. 8, though any equivalentform may be emplo ed.

'lyhe function ofthe various additional switches and contactors abovereferred to will be explained in connection with the description of theoperation which is as follows: Assuming that the controller 7 has beenmoved to the` left, a circuit is established which extends from the lineconductor 3, through the controller 7, the contact member 9b and theactuating coil 8 of the line contactor 5, to the line conductor 4. Theline contactor 5 is thereupon closed. This action causes the closing ofthe circuit eX- tending from the line conductor 3, through the conductor85, the contactors 90 and 88,

which occupy their closed positions when thev reversing contactors areopen, a resistor 91, the actuating coils 22, 22b and 22C, either inseries or in parallel, as desired (the parallel relation is heredisclosed), and the contactor 5 to the line conductor 4.

The relays 25, 26 and 27 are thereupon immediately opened. The openingof the relay 25 causes the closing of the switch 55a, whereupon acircuit is established from the line conductor 3, through the controller7, the contact member 9, the actuating coil 63, the switch 55et and theline contactor 5, to the yline conductor I 4. The reversing contactors59 and 60 are thereupon closed,

which instantlycauses the opening of the contactor 88 to lbreak thecircuit o-f the coils 22a, 22b and 22C. The relays 25, 26 and 27,however, will remain open, due to the fact that a new circuit is createdfor the coils 22a, 22b and 22, in parallel with the resistor 6, whichisnow traversed by current through the motor circuit as follows: from theline conductor 3, through the reversing contactor 59, the armature 1,the reversing contactor 60, the resistor 6 and the line contactor 5, tothe linecondu-ctor 4.

The circuit in parallel with the resistor 6 for the coils 22a, 221? and22c includes a resistor 92.. As the mot-or accelerates and itscounter-electromotive forcel increases, the voltage across theterminals. of the resistor 6 is decreased, whereupon the relays 25, 26and 27, which are of different weights, or controlled by springs ofdifferent strengths, are

successively closed to cause the closing .of the contactors l0, 1l andy12 to short-circuit the resistor in a manner that will be wellunderstood from the previous descriptions.

.n The circuits of the actuating coils 19, 20 and 21 may be controlledin the second position of the controller 7. The contactolr 67 creates aholding circuit for the coil 63 so as not to denergize this coil upontheclosing of the relay 25 and the consequent opening of the switch 55a.

To reverse the motor, the controller is actuated tothe right. The motorcannot be restarted in the reverse direction until the reversing-contactors both occupy their open.

positions, as illustrated, because a circuit for the actuating coils22a, 22"l and 22c must be made through the contactors 88 and 90, asabove described, and, furthermore, the circuit of the actuating coil 62of the reversing contactors 58 and 61 cannot lbe made until the coils22a, 22b and 22c have been energized, the coil 22a. causing the closingof the switch 55a to establish the circuit of the coil 62. Provision isthus made for preventing. restarting the motor until properconditionsobtain.

A study of the system of Fig. 9 will'show that the switch 55a performsthe function of the contact members 55, 56 and 57 of Figs. l

e 5, 6 and 8. In the systems of these figures,

it would be possible to substitute Afor the contact members 55, 56 and57 corresp'nding contact members on the armature 33,

whichwould control the closing of the preliminary circuits when thearmature 33 is in the open position. Thus, in the system of .Fig 6, thecontact member 55 may be identical 'with the contact member 45 and thecontact members 56 may be placed on the other side of the contact member48, so that the contact members 45 and 48 would be closed when thecontact members 45 and 55 would be open, and vice versa. The projection54 (Fig. 4) could then be omitted. Such changes are thought to beobviousto those 4skilled in the art and are within the scope of minvention. Other changes will be mani est to those skilled in theelectrical art.

My invention, furthermore, may' be employed in alternating-current, aswell as direct-current systems. I desire, therefore, not to be limitedSave as is indicated by the appended claims.

I claim as m invention: 1. The combination with an electric circuit anda pair. of .reversing switches there-r for, of actuating coils for saidswitches, means for energizing one of sald coils to cause the ,closingof' the correspondingl switch and means for preventing the energizationofsaid other coil fora predetermined length of time after thedenergization of said first coil to prevent the closing l system forelectric moy resistor in circuit therewith, a plurality of meansdependent upon said last named means for governing the closing of saidcontrollin switch. l

5. T e combination with vanelectric motor having an armature, a resistorin'4 cir- Cuit therewith, a pair of reversing switches, a plurality ofswltches for short-circuiting said resistor and a relay for each of saidswitches,I of means for preventing the operation of said motor in thereverse direction with said resistor initially short-cirouited upon theopening of one of said reversing switches and the closing of another ofsaid reversing switches.

6. The combination with an electric motor having an armature, a resistorin circuit therewith, and a switch for controlling the circuit of saidmotor, of a coil in shunt relation to said resistor, a pair of armaturescontrolled by saidcoil, means for preventing the closing of one of saidarmatures until after the closing of said other armature, a switchcontrolled b said one armature for short-circ'uiting said resistor, andmeans controlled my said other armature for controllin the closing ofsaid switch.

7 T e combination with an electric motor, a resistor, and a coil incircuit therewith, of an armature controlled by said coil, a switchcontrolled by said armature for short-circuiting said resistor and saidcoil, a second coil controlledby said switch for controlling saidarmature after said first coil is shortcircuited and means for causingsaid coils to oppose each other upon the reversel of said motor. Y

8. The combination with an electric motor, a resistor in circuittherewith and a pair of reversing switches'for said motor, of a coil, aswitch for closing the circuit of said coil when said switch occupies anormal position and for closing the circuit of said motor when itoccupies a second position, an armature controlled by said coil forcausing said thirdswitch to be actuated to said second position yandmeans controlled by saidarmature for short-circuiting said resistor.

9. The combination with an electric mofirst coil'into circuit tomaintain tor, a resistor in circuit therewith, of means forshort-circuiting said resistor, a coil, means controlled by said coilfor establishlng the circuit of said motor, means for thereupondenergizing said coil, a second coil for effecting the short-circuitingof said reslstor, said second coil being thereupon deenergized, andmeans for reinserting said said resistor short-circuited.

10. The combination with an electric motor, a resistor, and a coil inparallel therewith, of an armature controlled by said coil, a switchcontrolled by said armature for closing the circuit of said motor, aswitch controlled by said armature for short-circuitlng said resistorand a second coil controlled by the second switch for controlling saidarmature after said resistor is shortcircuited.

11. The combination with an electric circuit comprising a translatingdevice and a c oil in parallel therewith, of a pair of armaturescontrolled by said coil, means controlled by one of said armatures forclosin sald circuit and means controlled by the other armature forshort-circuiting said translating device.

12. In a reversing system for electric motors, the combination with amotor having an armature and a resistor in circuit therewith, of aplurality of switches for controlling sa'id resistor, a switch forpartly closing the circuit of Said motor, means for normally maintaininsaid last-named switch closed and said rst-named switches open, andmeans for preventing the reversal of said motor until said switchesoccupy said normal positions.

13. IThe combination with an electric motor having an armature and aresistor in circuit therewith, of a coilY in shunt relation to saidresistor for eii'ecting the short-circuiting 'of said resistor and meansfor preventing the reversal of said motor until the reversal of themagnetism of said coil.

14. The combination'with an electric motor having an armature, aresistor in circuit therewith, and a switch for short-circuiting saidresistor, said switch having an actuating coil, of means for startingsaid motor and me ns for preventing the short-circuiting of s idresistor after the reversal of'said motor until after the reversal ofthe magnetism of said coil. l

15. The combination with an electric motor having an armature, aresistorin circuit therewith, and 'a source of current for said motor,yof a switch for closing the circuit of said motor, a plurality ofswitches for shortcircuiting said resistor, a relay for each of saidshort-circuiting switches, means controlled by the, voltage of saidresistor for closing said relays, means controlled by the refr/2,0157Avoltage of said source for maintaining said relays closed, means foropening said circuit-closing switch before reversing the current 1n saidarmature, said voltage-controlled means thereupon becoming inoperative,means for reclosing said circuit-closing switch and means for preventingthe simultaneous closing thereupon of said switches for short-circuitingsaid resistor.

16. The combination with an electric Inotor, a resistor, a switch forclosing the circuit of said motor and a switch for effecting theshort-circuiting of said resistor, of an actuating coil for each of saidswitches, means for energizing the coil of the second switch when saidfirst switch occupies an operative position, and means for energizingthe coil of the first switch when said second switch occupies aninoperative position.

17. The combination with an electric motor, a resistor and a switch forclosing the circuit of said motor, of a switch for effect-v ing theshort-circuiting of said resistor and having an actuating coil, meansfor energizing said coil when the first switch occupies an inoperativeposition and means for maintaining said coil energized after said firstswitch has been actuated to an operative po- Sition.

In testimony whereof, I have hereunto subscribed my name thisl 30th dayof July, 1918.

HENRY D. JAMES.

